Different types of electronic engine controllers are known in the art. Such controllers typically measure various engine parameters including engine speed, transmission output speed, and a desired engine speed command to produce a fuel delivery signal as a function of the measured parameters in connection with a fuel delivery map or a rack position map stored in memory.
In prior electronic engine controllers the fuel delivery signal causes the fuel injector (or rack position in an engine without fuel injectors) to inject a particular volume of fuel into a particular engine cylinder. The power produced by the volume of fuel depends on the energy content of the fuel, which varies with the density of the fuel. These prior art controllers cause a desired volume of fuel to be delivered to the individual engine cylinders. That volume will correspond to a desired energy content of the fuel so long as the fuel is at an appropriate density. However, because the fuel delivery map used by such controllers is calculated for a predetermined fuel density, it is difficult to precisely control the power produced by the engine when the density of the fuel varies from that predetermined density. In those cases, the delivered volume of fuel will produce more or less power than desired because of the increased or decreased energy content resulting from the decreased or increased density of the fuel, respectively.
It would be preferable to have an engine controller capable of delivering a compensated fuel delivery command that adjusts delivered fuel volume as a function of the density, and thus the energy content, of the fuel. The present invention is directed toward overcoming one or more of these drawbacks associated with previous electronic controllers.